The electrical capacity question does not change. What changes is the equipment listing and the installation environment. The Alternative Fuels Data Center (retrieved 2026-11-11) says residential equipment is frequently installed in garages, that outdoor installation and use are also safe — even if the vehicle is being charged in the rain — and that outdoor installations require outdoor-rated equipment. Indoors, a plug-in EVSE on a correctly installed receptacle is common. Outdoors, many electricians and some municipalities prefer or require a hardwired, weather-rated unit, with fittings and a disconnect suited to a wet or damp location.
Practical differences to go over with the electrician, not to settle from a website diagram:
- The EVSE must be listed for the location (outdoor / wet or damp as applicable).
- Strain relief, ingress rating, and a way to keep the connector off the ground matter more outside.
- A longer feeder run, trenching to a detached parking pad, or a pedestal can dominate the cost; see the installation-cost page for dated national ranges, which already separate some indoor and outdoor figures.
- GFCI, disconnect, and receptacle rules are adopted locally. This page does not prescribe them.
Capacity still comes first: use the calculator, then have a licensed electrician design the indoor or outdoor installation under permit.
This is not a permit calculation, a utility approval, or a substitute for a licensed electrician, HVAC contractor, or the authority having jurisdiction. Panel Headroom is an independent educational site. It is not a utility, a certification body, or a contractor. Electrical and generator work that is done incorrectly can cause fire, shock, or carbon monoxide poisoning. Use the adopted electrical code and manufacturer instructions; pull permits where required.